1. Field of Invention
The present invention relates in particular to a pump for mounting on a receptacle, and serving to dispense a substance in a head-up or a head-down position.
2. Description of Related Art
French Patent Application No. FR 2 528 122 discloses a pump enabling a substance to be dispensed in a head-up or a head-down position, and comprising a pump body with a moving assembly in the pump body and co-operating therewith to define a pump chamber of variable volume.
The pump body has a lateral opening enabling the substance contained in the receptacle to penetrate into the pump chamber when the pump is used head-down. The moving assembly has a lip enabling the above-mentioned opening in the pump chamber to be isolated after it has been moved a certain distance into the pump body.
Such a pump has two helical springs which are in contact with the substance, and that can lead to problems of compatibility between the substance and the metal of the springs.
In addition, that pump has a relatively large number of parts, which is reflected in its manufacturing cost.
Finally, if the pump is held head-down for a long period, it can happen that the substance will leak out, particularly if the substance is not very viscous.